During the long way of evolution, one of the tremendous achievements of human being is the domestication of various animals and plants. These events have completely altered our life. Although we are benefiting from these creatures everyday, but for the majority of them, their underlying domestic mechanisms are still open to debate. For example, chicken is one of the most important poultry in our daily life. Most of us may accept the point that its ancestor is red junglefowl, but the arguments of its domestication have never stopped since the time of Darwin.
To help to clarify this question, Mitochondrial DNA (mtDNA) has been frequently used as the molecular marker to trace the history of domestic chicken. But in the relevant previous researches, the relatively small size of control region and its high mutation rate keep make the construction of matrilinealgenealogy difficult.
Under these circumstances, Prof. ZHANG Yaping’s research team (Kunming Institute of Zoology, the CAS) adopted the fine-grained mtDNA phylogenomic analysis to get deeper insights into the detailed history of chicken origin. A total of 4938 mtDNA fragments have been investigated, which include 2843 previously published and 2095 de novo units from 2044 domestic chickens and 51 red junglefowl. Meanwhile, 50 mtDNA complete genomes have been sequenced and then the mtDNA phylogeny of chicken has been reconstructed.
Those analysis shows that the common haplogroups A–G were shared by domestic chickens and red junglefowl. And the phylogeny lineages from the red junglefowl were mingled with those of the domestic chickens. In other terms, chicken was domesticated recently, and/or involving substantial gene admixture with the red junglefowl. Moreover, these local chicken domestication events involve South Asia, Southwest China and Southeast Asia.
According to Prof. ZHANG, by providing updated phylogenies, this study expands the perspectives into the complex history of chicken domestication. Moreover, attribute to the close relationships between chicken and human being, as chicken could be easily carried during human dispersal and migration, the domestic chicken dissemination and its mtDNA data also facilitates the uncovering about human past in the Holocene.
The main findings of this work have been published online in Heredity (doi: 10.1038/hdy.2012.83): http://www.nature.com/hdy/journal/vaop/ncurrent/abs/hdy201283a.html.